Servo Stock, The Future Of 3D Printers

printerIf you think about it, the RepRaps and other commercial 3D printers we have today are nothing like the printers that will be found in the workshops of the future. They’re more expensive than they need to be, and despite the RepRap project being around for a few years now, no one has cracked the nut of closed loop control yet. [mad hephaestus], [Alex], and [Will] over on the Hackaday Projects site are working on the future of 3D printing with the Servo Stock, a delta printer using servos and closed loop control to build a printer for about a quarter of the price as a traditional 3D printer.

The printer itself is a Kossel derivative that is highly modified to show off some interesting tech. Instead of steppers, the printer has three axes controlled by servos. On each axis is a small board containing a magnetic encoder, and a continuous rotation servo. With this setup, the guys are able to get 4096 steps per revolution with closed loop control that can drive the servo to with ±2 ticks.

The electronics and firmware are a clean sheet redesign of the usual 3D printer loadout. The motherboard uses a Pic32 running at 80MHz. Even the communication between the host and printer has been completely redesigned. Instead of Gcode, the team is using the Bowler protocol, a system of sending packets over serial, TCP/IP, or just about any other communications protocol you can think of.

Below is a video of the ServoStock interpreting Gcode on a computer and sending the codes and kinematics to the printer. It seems to work well, and using cheap servos and cut down electronics means this project might just be the first to break the $200 barrier for a ready to run 3D printer.

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Breaking Open The Quirky Nimbus

Nimbus

The Nimbus is a little Internet-connected device put out by a company called Quirky. It features four analog dials, each with graphic LCDs, with WiFi connectivity to show you how many tweets you’ve made in the past day. You know, in case you forgot, or something.

[Edu] didn’t find the social media-oriented Nimbus very useful, but Internet connected analog gauges are just so cool, so out came the screwdriver and the writing of new firmware commenced.

Inside the Nimbus there’s an SPI Flash, PIC micro, and an Electric Imp, a tiny ARM microcontroller and WiFi adapter stuffed inside an SD card. The Imp is always tied to a cloud service, in this case, a Quirky-lined cloud, but the folks at Quirky were keen to help [Edu] in his quest for better firmware.

After figuring out all the traces, [Edu] wrote a simple firmware that can control everything there is to control – the dials, displays, two buttons, and a speaker. So far he’s put some graphics on the display and PWM’d the theme from Monkey Island. This is just scratching the surface of what the device can do – [Edu] can still make use of the WiFi connectivity, and those dials can do much more than spin around in circles.

Monkey Island video below.

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The Three Chip Retrocomputer

3chip

Where homebrew computers are usually complex bundles of wires and chips, [Mike]’s own single board computer is not. It’s a three-chip computer with only a CPU, RAM, and a microcontroller that is able to emulate the retrocomputers of yore.

Normally, a homebrew computer project requires some amount of ‘glue’ logic – a few NAND, OR, or inverters to combine signals and send them where they’re needed for address decoding. This tiny pocket computer doesn’t need any of that; all the address decoding is done on a 40-pin PIC microcontroller.

With 64kB on the PIC 18F46K22, there’s enough space for all the address decoding logic, space for a pseudo ACIA mapped onto the $DF page, and a ROM image that provides a monitor program and a copy of BASIC. Basically, with the addition of a USB to serial adapter, this is a three chip 6502 single board computer, and with the right ROM monitor can emulate an Apple I, Woz monitor included.

Yes, 6502 projects are a dime a dozen, but [Mike]’s work with the address decoding logic on the microcontroller is top-notch. There are a few remaining chip select lines in his schematic, and with another microcontroller it would be easy to add VGA out, a compact flash adapter, or some other really cool peripherals. Good thing there’s an expansion port on this thing.

Single Digit Numitron Clock

numitronClock

The above may look like a Nixie tube, but it’s a Numitron: the Nixie’s lower-voltage friend, and part of [pinomelean’s] single-digit Numitron clock. If you’re unfamiliar with Numitrons, we suggest you take a look at our post from a few years ago, which includes a helpful tutorial to catch you up to speed.

[pinomelean] built this little device to capture a steampunk-ish look on the cheap for a clock small enough to fit on a wrist. The build uses a PIC16F84A uC and a 4MHz crystal on a custom PCB. A small button on the side lets the wearer set the time. Similar to the Vibrating Timepiece from last month, the Numitron clock isn’t perfect, though it is more accurate: gaining only one minute every 3 days.

Check out the video after the break to see it being set and keeping track of the time. It may take a moment to understand how to read the clock, though. Each of the four LEDs indicates where the number in the Numitron tube belongs. The LEDs light in sequence from left to right, displaying the clock one digit at a time.

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Tic Tac PIC Pack: A Pocket Programmer

Sure, mint tin housings are great. But you have to defend against shorts, and cutting out holes for ports and buttons is dangerous business. [Daniel] prefers plastic, and he tipped us off about a PICKit2 clone that he designed to fit inside of a tic tac box.

Almost all of the components were salvaged except for the microcontroller and the connectors. He wound his own inductor using the ferrite core from a CFL. [Daniel] had to make a few improvisations for this project. He didn’t have a 20MHz crystal, so he used a 12MHz crystal and tweaked the fuse bits after burning the firmware.

To save space on the board, he soldered wires to RESET, VCC, GND, PGD, and PGC to program the firmware and then removed the wires. The only trouble he had with it was more or less easily solved by replacing two transistors.

You may remember that we linked to his USBasp programmer in a mentos container a few months back. We figure [Daniel] must have some pretty fresh breath.

ARM Debugger for Nearly One Dollar

Oh that title is so misleading. But if you squint your eyes and scratch your noggin it’s almost true. Thanks to the hard work of [Peter Lawrence] it is now possible to hack together an extremely inexpensive CMSIS-DAP ARM debugger.

Let’s talk about function and we’ll get back to cost later. CMSIS-DAP is a standard that gives you the kind of breakpoint control you expect from a proper debugger. In this case [Peter] implemented the standard using 4k words of space on a PIC 16F1454. This lets it talk to the debug port on ARM chips, and the bootloader (also written by him) doubles as a USB-to-UART bridge. Boom, done. OpenOCD (and a couple of other software packages) talks to the PIC and it talks to the ARM. Nice.

Back to the cost question. You can get a 16F1454 for nearly a dollar when you order in quantity. If you cut up an old USB cable, recycle some jumper wire, and already have power and decoupling on hand, you’re in business for nearly one dollar.

Happy Birthday, Son. Here’s Your Very Own Claw Machine

mrclawIf [Will Baden] is in the running for Father of the Year, he’s a shoe-in. His son requested a robot-themed birthday party, so [Will] did what any superhero father would do and built him a toy claw machine.

[Will] harvested many of the parts from copy machines: both the 5V and 24V power supplies, the limit switches, 2/3 of the motors, and the 24V solenoid coil in the claw. The carriage is from a commercial printer. He made many of the mounts, including the ones holding the 3 stepper motors from Pololu.

A PIC16F870 is running the show. [Will] programmed it in assembly using Timer2 for stepper pulsing and RB0 interrupt to drop the claw when the button is pushed. He also added a WDT to get out of code trouble if needed. The claw’s solenoid is driven by a ULN2001A Darlington array. [Will] put a kickback diode on the coil so the pulses don’t go farther than they need to. He formed the fingers of the claw by bending pieces of brake line.

Not your kind of claw? Check out these incredible Wolverine claws!

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